lib.updateManyAttrsByPath

Update or set specific paths of an attribute set.

Takes a list of updates to apply and an attribute set to apply them to, and returns the attribute set with the updates applied. Updates are represented as { path = ...; update = ...; } values, where path is a list of strings representing the attribute path that should be updated, and update is a function that takes the old value at that attribute path as an argument and returns the new value it should be.

Properties:

• Updates to deeper attribute paths are applied before updates to more shallow attribute paths

• Multiple updates to the same attribute path are applied in the order they appear in the update list

• If any but the last path element leads into a value that is not an attribute set, an error is thrown

• If there is an update for an attribute path that doesn't exist, accessing the argument in the update function causes an error, but intermediate attribute sets are implicitly created as needed

Type

updateManyAttrsByPath :: [{ path :: [String]; update :: (Any -> Any); }] -> AttrSet -> AttrSet

Examples

updateManyAttrsByPath [
  {
    path = [ "a" "b" ];
    update = old: { d = old.c; };
  }
  {
    path = [ "a" "b" "c" ];
    update = old: old + 1;
  }
  {
    path = [ "x" "y" ];
    update = old: "xy";
  }
] { a.b.c = 0; }
=> { a = { b = { d = 1; }; }; x = { y = "xy"; }; }

Noogle detected

• lib.attrsets.updateManyAttrsByPath